DOC: add dev setup description for PRs to local repo (#9674)
DOC: add dev setup description for PRs to local repo (#9674)

* DOC: add dev setup description for PRs to local repo

* WIP: add colons for markdown rendering

* WIP: add checkout of unmerged PR to local branch

* DOC: remove git config instructions in favor of manual pr to local

Stefan-Endres/scipy,matthew-brett/scipy,tylerjereddy/scipy,lhilt/scipy,lhilt/scipy,pizzathief/scipy,jamestwebber/scipy,e-q/scipy,matthew-brett/scipy,WarrenWeckesser/scipy,e-q/scipy,perimosocordiae/scipy,arokem/scipy,zerothi/scipy,WarrenWeckesser/scipy,andyfaff/scipy,tylerjereddy/scipy,zerothi/scipy,Stefan-Endres/scipy,andyfaff/scipy,Eric89GXL/scipy,mdhaber/scipy,ilayn/scipy,mdhaber/scipy,scipy/scipy,WarrenWeckesser/scipy,jor-/scipy,pizzathief/scipy,gertingold/scipy,e-q/scipy,grlee77/scipy,e-q/scipy,aarchiba/scipy,endolith/scipy,tylerjereddy/scipy,gertingold/scipy,endolith/scipy,ilayn/scipy,vigna/scipy,nmayorov/scipy,lhilt/scipy,scipy/scipy,scipy/scipy,rgommers/scipy,perimosocordiae/scipy,perimosocordiae/scipy,arokem/scipy,aarchiba/scipy,aeklant/scipy,vigna/scipy,arokem/scipy,pizzathief/scipy,ilayn/scipy,tylerjereddy/scipy,Eric89GXL/scipy,person142/scipy,grlee77/scipy,person142/scipy,mdhaber/scipy,aarchiba/scipy,arokem/scipy,lhilt/scipy,gertingold/scipy,anntzer/scipy,endolith/scipy,WarrenWeckesser/scipy,arokem/scipy,anntzer/scipy,jor-/scipy,WarrenWeckesser/scipy,zerothi/scipy,vigna/scipy,Stefan-Endres/scipy,aeklant/scipy,gertingold/scipy,grlee77/scipy,jor-/scipy,grlee77/scipy,WarrenWeckesser/scipy,lhilt/scipy,andyfaff/scipy,Eric89GXL/scipy,Eric89GXL/scipy,jamestwebber/scipy,rgommers/scipy,e-q/scipy,mdhaber/scipy,jamestwebber/scipy,aeklant/scipy,scipy/scipy,zerothi/scipy,endolith/scipy,matthew-brett/scipy,Eric89GXL/scipy,pizzathief/scipy,rgommers/scipy,perimosocordiae/scipy,matthew-brett/scipy,jor-/scipy,nmayorov/scipy,scipy/scipy,endolith/scipy,tylerjereddy/scipy,person142/scipy,pizzathief/scipy,andyfaff/scipy,andyfaff/scipy,mdhaber/scipy,Stefan-Endres/scipy,vigna/scipy,aarchiba/scipy,aeklant/scipy,rgommers/scipy,scipy/scipy,matthew-brett/scipy,anntzer/scipy,jamestwebber/scipy,person142/scipy,jamestwebber/scipy,aarchiba/scipy,gertingold/scipy,person142/scipy,ilayn/scipy,grlee77/scipy,ilayn/scipy,nmayorov/scipy,perimosocordiae/scipy,andyfaff/scipy,vigna/scipy,anntzer/scipy,aeklant/scipy,endolith/scipy,anntzer/scipy,nmayorov/scipy,perimosocordiae/scipy,Eric89GXL/scipy,jor-/scipy,Stefan-Endres/scipy,anntzer/scipy,mdhaber/scipy,ilayn/scipy,Stefan-Endres/scipy,zerothi/scipy,zerothi/scipy,rgommers/scipy,nmayorov/scipy